ISSN:0030-4921    

DOI:10.1002/mrc.1270071219

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractFor quantitative analysis by NMR spectroscopy with Fourier transform, the usual experimental conditions have to be partly modified. Careful regulation of the delays between the different phases of the process is particularly important. The filters of the spectrometer and the calculations on the free induction decay are important causes of error. Precise results are given.

ISSN:0030-4921    

DOI:10.1002/mrc.1270071202

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractL'attribution des signaux de RMN du13C de laN‐(phényl‐1 cyclohexyl) pipéridine et de quelques dérivés 4‐substitués, sous forme de chlorhydrates dans H2O et CDCl3, a permis une étude conformationnelle. Celle‐ci confirme la plus grande stabilité des composés dont le groupe pipéridinium est équatorial. Certaines particularités dans les glissements chimiques observés paraissent attribuables à des déformations du système cyclohexanique, étroitement liées au

ISSN:0030-4921    

DOI:10.1002/mrc.1270071203

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractEthyl 2‐cyano‐3‐methyl‐4‐phenyl‐2‐pentenoate was obtained as a mixture of two geometric isomers. An aromatic solvent induced shift experiment and calculations of the difference in the chemical shifts of methyl protons linked to the double bond lead to the assignation of the geometry of

ISSN:0030-4921    

DOI:10.1002/mrc.1270071204

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractThe analysis of the NMR spectra of seleninium and 1‐and 2‐benzoseleninium cations, recorded in deuterotrifluoroacetic acid, is reported. The effects of condensation on the spectral parameters of the protons of the seleninium ring were examined with particular reference to the shift to higher values of δ: this was consistent with theqvalues calculated by the HMO method. The3J(HH) and4J(HH) variations, including an interesting variation regarding the through‐selenium4Jcoupling, are also dis

ISSN:0030-4921    

DOI:10.1002/mrc.1270071205

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractA full analysis of the 60 MHz1H NMR spectra of heterocyclic analogues of 1,3‐indandione [N‐(2‐bromoethyl)‐phthalimide, phthalic anhydride and thiophthalic anhydride] and of 1,2‐indandione (N‐methylisatin, coumarandione and 2,3‐dihydrothionapthene‐2,3‐dione) has been carried out. The protons of the symmetric compounds resonate at lower fields than those of the asymmetric ones and the protonorthoto the CO function is more deshielded than the protonorthoto the heteroatom. Coupled Hartree‐Fock perturbation theory has been applied to estimate the ring current contributions to the proton chemical shifts and to the magnetic susceptibilities. MO calculations based on the finite perturbation theory at the CNINDO levels provide information on the relative importance of σ and π pathways for the vario

ISSN:0030-4921    

DOI:10.1002/mrc.1270071206

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractCarbon chemical shifts and direct13C1H coupling constants of 2‐endo‐methyl‐5‐norbornen‐2‐exo‐ol, 2‐exo‐methyl‐5‐norbornen‐2‐endo‐ol, 2‐endo‐methylnorbornan‐2‐exo‐ol and 2‐exo‐methylnorbornan‐2‐endo‐ol have been measured from single samples

ISSN:0030-4921    

DOI:10.1002/mrc.1270071207

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractL'étude complète de cette série permet de justifier l'emploi des systèmes d'incréments pour l'identification des raies de résonance du proton et du carbone 13. Ces incréments peuvent être obtenus en première approximation par l'étude des dérivés monosubstitués ou par comparaison avec les dériv

ISSN:0030-4921    

DOI:10.1002/mrc.1270071208

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractThe paramagnetic contribution to the13C and1H nuclear relaxation rates in the ethanol‐Mn(II) system has been calculated. BothT1andT2experiments have been performed by means of Fourier transform and partially relaxed Fourier transform NMR spectroscopy. The correlation times for the dipolar and scalar parts have been discussed and evaluated. Calculations of distances and of hyperfine coupling constants have been carried ou

ISSN:0030-4921    

DOI:10.1002/mrc.1270071209

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY

摘要:

AbstractA spectrometer for recording14N NMR spectra is described. The14N NMR linewidth versus pH dependences of several amino acids and related molecules are presented. It appears that the linewidth pH profile of each amino acid is unique. Linewidth minima occur between pH 6 and 8. A discussion on how14N NMR linewidths of amino acids might give information on weak association is given.

ISSN:0030-4921    

DOI:10.1002/mrc.1270071210

出版商:John Wiley&Sons Limited    

年代:1975

数据来源: WILEY